Why won't my kidney stone pass?

So maybe a week ago i woke up in agony, went to the er and they told me i had a kidney stone. After staying at the er and being pumped full of pain killers and fluids, the pain went away and I haven't felt it since. Here's the problem, I've been straining all my pee and I still haven't caught the damn thing. This stone was 6mm by 3mm so it's not a small stone. Where the hell did it go? Could it trigger another attack? Will it hurt on the way out? Any information would be helpful. It's been a week and I haven't even felt mild discomfort. could it have dissolved?